BACKGROUND: The authors reviewed the incidence of hemorrhage after laparoscopic Roux-en-Y gastric bypass (LRYGBP). The purpose of this study was to determine the incidence of this complication and to evaluate various treatment options. MATERIAL AND METHODS: The records for 450 consecutive patients who had undergone LRYGBP over a 30-month period, were retrospectively reviewed. In all patients, the abdominal cavity had been drained with 2 19-Fr closed suction drains. The charts of patients who had developed an intraluminal or an intraabdominal bleed were chosen for further review. RESULTS: 20 patients (4.4%) developed an acute postoperative hemorrhage. The bleeding was intraluminal in 12 cases (60%), manifested by a drop in hematocrit, tachycardia and melena. The other 8 patients (40%) developed intra-abdominal hemorrhage, confirmed by large bloody output from the drains. 3 patients (15%) with intraluminal bleeding were unstable and required a reoperation. All others were successfully treated with observation, and 15 patients (75%) required blood transfusions. CONCLUSIONS: The diagnosis and treatment of acute intraluminal bleeding after LRYGBP represents a surgical dilemma, mainly due to the inaccessibility of the bypassed stomach and the jejuno-jejunostomy, as well as the risks associated with early postoperative endoscopy. The presence of large intra-abdominal drains allows for bleeding site localization (intraluminal vs intraabdominal) and for more accurate monitoring of the bleeding rate. Most cases respond to conservative therapy. Failure of conservative management of intraluminal bleeding, however, is more problematic and may require operative intervention. A treatment algorithm is proposed.